Method of multiple pointing stone chisel



P. P. BICKNELL METHOD OF MULTIPLE POINTING STONE CHISEL Jan. 1, 1935,

Original Filed April 25, 1930 Inventor Rainamlffliahwll rBy' Patented Jan. 1, 1935 sm presentiapplicatiomrelates to the; forming ofmu'l nle 'I1l'iis-subject matter is; divided 'sout of prior, 1 application Serial :No.;447.,222.; fliedAp'ril 125,119304:

: :In-ston'e= cutting-mdinotablyrin *the zranite industry; 2 among wthexyarious that have: become :standard- -isxrthatiiknownzlas the chisel or four This tool is one .subiected I the-.ouarters r of xthe jpyramidal :end outwardly" diagonally of the of the f' pyi'anrid:* This produced a} tool which hasubeen that imgenerlal usezfonyears, and-men ioning ofxthe tool was inventioniflv V l.; .The;1ifeaOfthe olclsfour point was short; but accepted-as inevitable as wastheslow and lahoriousibasis. :ofwits .forgin-g and I the known solution of the problem seemedcwthat 1 of MOIG'GMB andftabominutming; quartering and re-forgingx a 1 My concept of: the solution invoivedE a; sideratiumiotithe' geometric basis of the tool 0 of the four points which characterize it. Analyzed, the old tool points were truncated four sided pyramids having two of its lateral faces joined at right angles and along a perpendicular line. While, therefore, they did represent in assembly a regular four sided truncated pyramid and could be dissected by splitting, it was necessary to distort and re-shape them by forging to dispose them in their final positions.

My invention contemplates the formation of these pyramidal points in their ultimate position and posture with reference'tothe stock of the chisel. This I accomplish by swagings at right angles to each other and along the lines of the bisecting perpendiculars to the sides. of the square cross section of the stock. The swaging tool employed induces an end flow of the hot stock and is so constructed as to direct the metal forwardly to a point, there being no pos- 5Q sibility of any escape of the metal from the shaping tool or any bending or lateral displacement externally of the die during the swaging action. The only loss in metal is that resulting.

from friction which is only a fraction of an ounce for each tool swageds practically "priori'wi P esent" the, :general :deaign, ;;the:i;old-.,chisel gltf'uc r turallwquite :Itis;-ofiereater ;streng h? andqmorezreadilymmduoed 5:01; restored: 'Ihis-I ueriillustrated in heiaocompanyingdrawingrai.

iFigt aside iemorztheend of a piecefifv uaregxvhi eizstockgmzz ar ar sideview a of block in o i n n @e dw iii?- V, er nee aist e e. which constitutes the body;,qf

ewishsqtirom iw ee o, 1 a It ZMW 4 and from the original four point chisel in which the outer faces of the points were forged as near as possible in the plane. of the squared stock. While my invention is capable of producing a tool of this type, the formation of the points with inwardly inclined outer faces is advantageous and produces amore eflicient and longer life tool.

In producing the original four point chiselthe bar was first forged down to a pyramidal point which was splitatright angles to the pyramid faces. The four parts thus formed were then forged outwardly to the four corners of the stock as before described. The difiiculty as previously noted was thatthe points were not uniform and the weakest. tooth quickly broke thus destroying the utility of the tool.

To avoid this and provide a tool of maximum strength and one readily produced or reformed," I contemplate the development of the'teeth or Points Pin final position and posture. This vI accomplishby swaginghot against a rotating disc which as shown in Fig. 4 is a disc 11 supported on a shaft 13, and having a; peripheral channel 12 of W-shaped cross section.

In this operation the end of the portion B is forced against the channelled edge of the disc 11 so that the mid-angle of the W-shaped channel bears on the center line of the end and perpendicular to the sides of the stock. This forms in the end of the stock a central V-shaped valley and inclined-outer-walls- --..'Ihe sto,cl:; isthen turned 190 andflagain brought .aga'inst thedisc and these steps repeated until the points P are formed at the respective corners of the bar ;as in Figs. 1 and 2. Such points aresymmetrical: and of great strength. They nlay hemmed-at} a red heat with rapidity and convenience.

The edges of the outer walls or flangeqllf of the swaging disc 11 are ofa width or spacing to receive the heated end of the stock tobeworked upon, so that there can be -no lateral bending or displacement of the metal outside of the tool when the same is first thrust against the. swag-.2; ing disc, or of the teeth as they are developed. As shown inf Fig: mnedisc' is provided with a W-shap'ed edge; which, 'acting o'n the hot" stock bylateral simultaneous pressure on' 'opp'osite pairs of facesfor potential teeth-sidesytends to flow the-'samei rorwardlyinto -the 'v shaped channels between the flanges 11' and 11? toproduce' the inclined outer walls and 1? V-shaped valleys in the stock. The stocl when=pointed is somewhat' longer' than it'- wasbefore being pointed;-th'ere' has been -practically no loss of stock, and the resulting points are of uniform mass and strength and are all 6 may positioned with' re:- t nce t a es-me" he 'ie The chisel Y shank 5 may; be ,fsuppo'rtedon any suitable rest asjat l4 andfforced as desired axi any h di ion .o a riiw-v Th si n are only simplyindicated as the machine may be o1 any-siinple design. Y a

While the tool dl scussed is oi-the conventional mu: point tiiefilt1will"bef'iinderstood that "the number-of teeth or' points" might be varied and their shape changed, all without de arting from the spiritf'ofmy invention.

Wha I t t -er by Letters Patent {is v L'That metho of o'rxningf" the our -pyrami dal points of af one fiis'elof' squa're stock cross section which consists in heating "the end to be pointed'to workable condition, in dr'a'w and desire to secure mg the antse'ndwijse of the bariby succes's'ive die channels by the opposed resultant pressures of-Tthe-Jinclined channel side walls upon opposite 5 point faces in pairs during said successive traversin'gs in alternate lines of movement at right angles to each'other.

2.1 That 'methodlot-forming the four pyramidal pointsoi a fou'r point stone chisel of square stock'cross section-which consists in heating the end to be pointed to workable condition, in drawing the points endwise of the bar by successive relative traversings of 3 'a' rotating forming die atalternating right angleipositionings of the stock applied. with pressure diametrically of the die edge,i-'said 'diezedg'ef havin'gz. peripheralchannels: and inclinedvchannel walls of substantially- .W-'-shaped cross section, :whereby the points are progressivelyseparated rdown to the common base plane ofwtheapoint' group while their individual apexes are simultaneouslyldrawn out away fromsaid'basei'plane to the bottom of thedi'e channels by theopposed resultant pressures'ofzthe ihclined channelwalls upon opposite faces "of the :.p'oint. pairs during said-.s'uccessive traversingsin .alternate' lines 0f" movement at right anglesto each other; B'HI'hat -method 0f 3 forming a' -chiselpoint which consists in "heatinglthe end to be pointed to workable; condition; in drawing the point endwise of the barby'successiveI relative traversings of a rotating forming: die-nit alternating right angle positionings 'of thetstockapplied with pressure diametrically of the die edge, said die edge having a peripheral channel havinginclined walls oflthe' cross section of the; ultimate'pyramidal :point; whereby the =pointiis. drawn (out and away-from said baseplaneto the bottom of the die channel -'by the opposed resultant pressures of said inclined channel walls to the: desired pyramidalcontour of'thedinished point:

-:' 3 -l.: ZPUTNAM PJBICKNELLI 

